Conventional vending machines generally have a coin mechanism, into which a coin is placed, and a handle which is manually rotated to release an article from the machine, providing that a coin has been placed in the coin mechanism.
It is a common problem however, that coins of incorrect denomination and metal slugs are often fed into the coin mechanisms of vending machines in an attempt to defraud the vendor. Therefore, conventional vending machines include latch mechanisms which prevent rotation of the coin mechanism if a coin which is too thin, or if no coin at all, or if a grossly undersized coin, is used. These latch mechanisms normally comprise a blade which is biased perpendicularly into the recess of a coin receiving disc in which the coin is held. If a correctly sized coin is used, the blade merely runs over the face of the coin as the mechanism is rotated. However, if a grossly undersized coin or if no coin at all is located in the recess, the blade either snags between the coin and the walls of the recess or snags the walls of the recess, preventing rotation of the mechanism. However, this mechanism cannot detect if a slug or coin of a size similar to, but not equal to, a coin of the correct denomination is being used. Also, oversized coins or slugs are not readily detected.
In a further conventional mechanism, a lever is pivotally located to the side and above a rotatable coin receiving disc. One end of the lever is biased toward a recess in the disc in which the coin is received. If a correctly sized coin is used and the mechanism is rotated, the end of the lever runs on the rim of the coin and is lifted over the trailing edge of the recess. If the coin is too small, the end of the lever snags the trailing edge of the recess and prevents further rotation of the mechanism. This security mechanism is able to determine the diameter of the coin more accurately than the latching mechanism, but is susceptible to disengagement by means of wire, and the like, being pushed into the mechanism and used to raise the lever.
Unfortunately, both these conventional security mechanisms are not easily adapted to use with a coin mechanism which takes two coins in side-by-side relationship.
Another disadvantage of conventional coin mechanisms relates to the ability to circumvent the mechanism. One of the ways in which attempts are made to circumvent the coin mechanism in a bulk vendor is to apply a piece of two-sided tape or some glue to the face of a coin, and to then insert the coin into the coin receiving slot. The coin thereby adheres to the coin receiving recess, and as the coin mechanism is turned the coin either remains in the slot, permitting successive turns of the mechanism each of which allows merchandise to be dispensed, or jams the mechanism because a conventional sheer action coin discharging arm, which exerts only a radial force on the coin to extract it from the recess, is unable to overcome the force of the adhesive.
It is an object of this invention to provide a security mechanism for a coin mechanism which accurately determines the diameter of a coin placed in the mechanism.
It is further an object of this invention to provide a coin extraction device for a coin mechanism which prevents multiple dispensing and jamming when a coin is adhered to the coin receiving recess.